body {
	/*background: #eee;*/
	background: url("../img/dogbg.png") no-repeat;
	background-size: cover;  //只支持IE9+
-webkit-background-size: cover; //webkit核心
-moz-background-size: cover; //FF核心
-o-background-size: cover; //应该是Opera核心吧，反正不是IE的，就先不管它了
}

@keyframes mysnow {
	0% {
		bottom: 100%;
		opacity: 0;
	}
	50% {
		opacity: 1;
		transform: rotate(360deg);
	}
	100% {
		transform: rotate(0deg);
		opacity: 0;
		bottom: 0;
	}
}

@-webkit-keyframes mysnow {
	0% {
		bottom: 100%;
		opacity: 0;
	}
	50% {
		opacity: 1;
		-webkit-transform: rotate(360deg);
	}
	100% {
		-webkit-transform: rotate(0deg);
		opacity: 0;
		bottom: 0;
	}
}

@-moz-keyframes mysnow {
	0% {
		bottom: 100%;
		opacity: 0;
	}
	50% {
		opacity: 1;
		-moz-transform: rotate(360deg);
	}
	100% {
		-moz-transform: rotate(0deg);
		opacity: 0;
		bottom: 0;
	}
}

@-ms-keyframes mysnow {
	0% {
		bottom: 100%;
		opacity: 0;
	}
	50% {
		opacity: 1;
		-ms-transform: rotate(360deg);
	}
	100% {
		-ms-transform: rotate(0deg);
		opacity: 0;
		bottom: 0;
	}
}

@-o-keyframes mysnow {
	0% {
		bottom: 100%;
		opacity: 0;
	}
	50% {
		opacity: 1;
		-o-transform: rotate(360deg);
	}
	100% {
		-o-transform: rotate(0deg);
		opacity: 0;
		bottom: 0;
	}
}

.roll {
	position: absolute;
	opacity: 0;
	animation: mysnow 10s;
	-webkit-animation: mysnow 10s;
	-moz-animation: mysnow 10s;
	-ms-animation: mysnow 10s;
	-o-animation: mysnow 10s;
	height: 100px;
}

.div {
	position: fixed;
}